This division is engaged in investigating the underlying functionalities of hydrides behind the bonding states of hydrogen, and material design for the solution of energy and environmental issues based on the knowledge obtained. The main subject is the exploration of high-density hydrogen storage materials that provide the foundation for hydrogen technologies such as fuel cell. Actually, we design and synthesize the new complex and metal hydrides composed of lightweight metals with specific nanostructures, and analyze them using atomic/electronic characterizations and first-principles calculations. In addition to the hydrogen storage, we develop the wide research fields related to hydrides, e.g., lithium/sodium ionic conductors, and neutron shielding materials.